The Bhutanese Leading the way.
The 1020 MW Punatsangchu II project, which had to delay power production due to seepage in the ceiling of the power house, is aiming to start generating power for export by 17th December, which falls on the 117th National Day.
The dam water level had been lowered, and the Head Race Tunnel (HRT)and the Surge Shaft Chamber and other areas were examined in detail, but there was no obvious place from where water was going in to contribute to the seepage.
As a precaution, the joints in the HRT, spaced at 15-meter intervals, were treated with penetron coating, which consists of a cement-based mixture. The same coating was also applied to the surge shaft, and additional grouting was performed at the base of the surge shaft.
A false ceiling was also constructed below the ceiling to catch and drain away seepage water.
Water filling of the Dam was started from 27th November and right now the pen stock, surge shaft and HRT are being filled up with water. It will be done by 7th December, and the aim is to start trial runs from 8th December with the aim to officially start from 17th December.
Given the low level of the river, it will be possible to run only one unit of 170 MW. The hope is that if all goes to plan then from March onwards, when there is more glacial meltwater, two units can come online and as the river flow increases all units can come into play by monsoon.
Despite the implementation of these measures, in the event that seepage persists, a contingency plan has been devised to intercept and divert the water before it reaches the powerhouse. For this purpose, a borehole is being drilled to establish a connection between the adit and the pressure shaft, facilitating the controlled redirection of seepage flow.
Following the decision of the 18th Technical Group (TG) meeting held on 5th September 2024, the dewatering of water-conducting systems began on 7th September 2024, and was completed by 14thOctober 2024.
On dewatering of the water-conducting system, the seepages had reduced from 1200 liters per minute to 650 liters per minute showing some link.
According to a reliable source the tariff for the 1,020 MW Punatsangchu II project is likely to be Nu 5.25 per unit.
Given that the project is expected to generate 4,357 million units per year the total revenue expected in a year is Nu 22.874 billion.
